You can select the dropdownlist values in JS file or CSHTML file using View Data and the details will be stored in the view data. Then you can pass this ViewData to DAL Layer from controller and store it in Database.

You can use FormCollection to get the values in to your action method. Then create object based on the required properties and assign values to it and send to db logic method. For suppose we have customer object to store with some properties like _customerName, _gender.See the below lines of code for your idea.

public ActionResult Save(FormCollection form) { customer objcustomer=new customer(); try { objcustomer.customerName = Request.Form["cid"].ToString(); // cid is the id given for the dropdown in your cshtml. objcustomer.gender=Request.Form["gender"].ToString(); // gender is the id given for the dropdownlist in cshtml